a) Field of the Invention
This invention generally relates to metal picture frames, and, more particularly, to a method of manufacturing metal picture frames having multiple, anodized, colored regions.
b) Description of the Prior Art
A known and desired practice in the framing art is to mount a picture or painting within a multi-colored frame. Older wooden frames were painted in various colors as desired, using an appropriate mask to create a sharp transition between one colored region and an adjacent region of a different color. The prior art painting process required to introduce two adjacent colors tends to be labor intensive and does not lend itself well to the extruded aluminum frame commonly used today.
Another technique used to provide picture frames with multiple colored regions is called a xe2x80x9cpicture within a picturexe2x80x9d technique and involves the nesting or stacking of two (or more) frames together (i.e., one inside the other) wherein each frame displays a different color or texture. With this technique, an outer frame of a first color receives an assembled second frame having a second color. The second frame is sized to concentrically fit within the first frame. The two frames are typically clamped together from behind so that they appear as a single, multi-colored (two tone) frame assembly when viewed from the front. Such picture within a picture frame assemblies are disclosed in U.S. Pat. Nos. 5,367,802 issued to Rosenberg, U.S. Pat. No. 3,408,759 issued to Rotheraine et al., U.S. Pat. No. 481,117 issued to Naegele, U.S. Pat. No. 480,953 issued to Mauerhofer, and U.S. Pat. No. 197,738 issued to Lippe.
Although these prior art combination frames are aesthetically pleasing, they are difficult and expensive to manufacture, and time consuming to assemble. In particular, with such multi-frame assemblies, it is difficult to cut the corner miter joints of both (or all) frames accurately so that all stacked frames (inner and outer) appear aligned.
A great number of picture frames manufactured today are made from aluminum. Aluminum frames may be colored using any of several techniques including, for example, surface painting, surface covering (applying a colored layer to the frame surface, e.g., a colored adhesive film), and electro-chemical coloring techniques, such as anodizing and subsequent dyeing.
Anodizing processes are cost effective at coloring large quantities of aluminum frame stock during the manufacture of the frame assemblies. The resulting colored finish of an anodized and dyed frame is very thin, uniform, and durable.
The basic reaction in all anodizing processes is the conversion of an aluminum surface to aluminum oxide with the aluminum part serving as the anode of an electrolytic cell. It is well known to use dye baths to uniformly color newly anodized aluminum parts. Once immersed in a dye bath, the aluminum will take on the color of the dye by absorbing the dye colorant into the microporous structure of the newly anodized surface, thereby producing a uniform color throughout the entire exposed aluminum part. Dyes useful in coloring aluminum are also well known and include those disclosed in U.S. Pat. No. 3,264,142, issued to Wainer, which is hereby incorporated by reference.
In the framing industry, aluminum frames are typically colored using an anodizing/dye-immersion method; however, this technique is only suitable for uniform coloring of the aluminum part. The frames may similarly be colored using other coloring techniques, such as painting, using a single color, for example.
It would be beneficial to use anodizing and/or painting techniques to provide an aluminum picture frame that includes two or more regions of different colors.
Accordingly, it is an object of the invention to provide an improved method for making an aluminum picture having at least two different colors.
It is another object of the invention to provide a method for manufacturing such an aluminum picture frame easily and cost effectively.
It is another object of the invention to provide a method for manufacturing a multi-colored picture frame using painting and anodizing techniques having sharp defined boundaries between adjacent colored regions.
It is yet another object of the invention to provide such a multi-colored picture frame which overcomes the deficiencies of the prior art.
According to a first and preferred embodiment, aluminum frame stock is coated with a colored maskant. Selective regions of the coated frame stock are abraded, thereby exposing bare aluminum in those selective regions. The abraded frame stock is then anodized and dyed a second color so that the exposed regions absorb the second color, adjacent to the colored masked regions. The resulting frame includes first regions having a first color (the maskant) and second regions having a second color.
According to a second embodiment of the invention, aluminum frame stock is etched, anodized, and then dyed a first color. The frame stock having the first color is then abraded to remove selective regions of the first color, thereby exposing the aluminum in these regions. The abraded frame stock is then anodized and dyed a second color so that the abraded regions absorb the second color, resulting in the frame stock having first regions of one color and second regions of a second color. The two-colored frame stock may then be used to form picture frames.
According to a third embodiment of the invention, the aluminum frame stock is first etched, anodized, and dyed a first color. Selective areas of the frame stock are then protected using an etch-resistant mask. The colored, masked frame stock is then etched to strip the unmasked regions of the first color, thereby exposing the aluminum surface in those regions. The frame stock is then anodized again and dyed a second color so that the unmasked regions absorb the second color. The mask is then chemically removed, thereby exposing the underlying first color located adjacent to the second color.